563 
the Colony of Western Australia. 
simis arcuato-incurvis obtusis; articulis omnibus diametro 2 -3-plo-longioribus ; tetrasporis 
eilipsoideis numerosis secus pinnas sessilibus. Crevices of rooks, at half-tide, Eottnest 
(328). This is certainly near C. roseum in miniature. To the naked eye it looks very like 
Dasya ocellata, or like a bunch of little bottle brushes. 
309. Callithamnion dehile., n. sp. ; fronde pusilla (vix unciali) tenuissima ecorticata c£espitosa in- 
ferne quoquoversum superne distiche ramosa ; ramis paucis alterne divisis, ramis minoribus 
disticheramulosis, ramulis paten tissimis inferioribus simplicibus spinEeformibus superioribus 
furcatis v. subpinnulatis ; articulis inferioribus diametro 5-8-plo, ramulorum 3-4-plo-longi- 
oribus; tetrasporis solitariis ad ramulos sessilibus. Eottnest, rare (330). Unlike any Aus- 
tralian species; and most like some starved form of C. pohjsperinum, but of a very fragile 
substance and pale colour. 
310. Callithamnion radicans, n. sp.; nanum, parasiticum, velutino-caispitosum; fronde minutEi 
(2 lineas alta) basi fibrillis crispatis radicante, e basi ramosissima; ramis primariis alternis 
secundisve 2-3- ties decompositis, minoribus ramulisque secundis strictis ; articulis cylindra- 
ceis diametro 4-5-plo-longioribus; ramulis fructiferis prope basin ramorurn sparsis simpli- 
cibus v. parum ramosis; tetrasporis eilipsoideis terminalibus. OaZostera leaves, Fremantle 
(331). This resembles C. luzurians^ J. Ag., externally, but seems sufficiently marked by 
its rooting filaments and longer articulations. 
311. Callithamnion botryocarpum, n. nanum, penicillato-caespitosum; fronde minuta (1-1^ 
lineas alta) e basi ramosissima, ramis alternis v. secundis patentibus flexuosis nunc sub- 
squarrosis; articulis diametro 4-plo-longioribus; tetrasporis rnagnis triangule divisis in glo- 
merula ad axiles ramorurn densissime aggregatis; antheridiis, botryoideis e quoque fere 
articulo ramorurn ssepe evolutis. Abundant on Chorda lomentaria, at King George’s Sound, 
in August (324). Externally very like C. Daviesii, but I suppose distinctly characterized 
by its fruit. The tetraspores are very large for this section of the genus. The antheridia 
resemble little clusters of grapes, ranged along the upper branches of fertile specimens. 
312. Callithamnion sparsum, Harv.(?) Parasite on Sporochnus, at Garden Island. This requires 
to be compared with British specimens; and also with Kiitzing’s C.humile from the Cape of 
Good Hope. It is quite different from either of the preceding, very sparingly branched, of 
a deep purple colour, and rather rigid texture, with very short articulations. 
Series III.— CHLOROSPERMEiE. 
Order L— SIPHONACEiE. 
313. Cauleepa Ag. ? On the reefs,' Eottnest. A much dwarfer, and more branching 
form than that figured by Turner, if the same. Possibly my plant may be rather akin to 
C. lentifera, J. Ag. (207). 
314. Caulerpa toeufrews, Mont.? Extremely abundant on the surface of shallow reefs, exposed 
at low water, Eottnest. I have not compared with Montagne’s plant (208). 
315. Cauleepa cylindracea, Sond. King George’s Sound, rare (54). 
VOL. XXII. 4 D 
